Definition
Damage caused to an aircraft, particularly to turbine engines, propellers, tires, or airframe surfaces, by loose objects ingested into or struck by the aircraft. Common sources include rocks, gravel, hardware, tools, ramp debris, ice, and birds. Commonly abbreviated FOD, which is also used to refer to the loose objects themselves.
Plain English
Damage to an aircraft caused when a loose object — like a stone, bolt, or piece of debris — gets sucked into an engine, kicked up by a propeller, or strikes the airframe.
Context Anchor
Seen in preflight inspections, ramp and runway safety, engine inspections, maintenance reports, and discussions about keeping aircraft operating areas clean.
Derivation
Foreign comes from older words meaning outside. In this term, the object is foreign because it is outside where it belongs around the aircraft, not because it comes from another country.
Why Pilots Care
Can lead to engine failure, structural damage, or emergencies, resulting in aborted flights, expensive repairs, and safety risks.
Analogy
A small stone in a household fan can chip the blades or stop the fan. Around an aircraft, a small object can cause much more serious damage.
Intuition Check
Foreign does not mean from another country here. It means an object or material that does not belong in that place around the aircraft.
Example Sentence 1
The pilot did a careful walk-around of the ramp area to check for foreign object damage hazards before starting the turbine engine.
Example Sentence 2
Mechanics traced the compressor stall to foreign object damage from loose hardware left in the intake.